1. Field of the Invention
The present invention relates to a toner cartridge installation structure for an electrophotographic machine.
2. Description of the Related Art
There are used various electrophotographic machines, including electrostatic copiers, laser facsimile machines, laser printers and the like, for generating images by utilizing technique known as electrostatic photography. A typical electrophotographic machine uses a photosensitized medium, in the form of a drum or a belt, having a photosensitized surface made of photoconductive insulating material. A charging unit is used to place a uniform electrostatic charge over the photosensitized surface preparatory to imaging. Then, a desired light image is either projected by an optical system or drawn by a laser beam scanner on the photosensitized surface, to form an electrostatic latent image on the surface. Thereafter, the latent image is developed with a developing material, powdery material referred to in the art as toner, to form a powder image on that surface. The powder image is then transferred to and fixed onto a support surface, such as a surface of a sheet of paper.
For developing the latent image, such electrophotographic machines include a developer unit, which is designed to apply toner to the photosensitized surface having a latent image formed thereon, and a toner dispenser for dispensing toner into the developer unit. A typical toner dispenser comprises a dispenser roller cooperating with a toner reservoir, which may be also referred to as a toner hopper. The dispenser roller may comprise a foam roller, for example. During development process, toner is either continuously or periodically dispensed from the toner reservoir into the developer unit by means of the dispenser roller.
The toner reservoir reserves a supply of toner therein. After use of the machine for a certain length of time, such as several weeks or months, the supply of toner in the toner reservoir is depleted, necessitating toner replenishment in the machine. In order to allow the user to conduct toner replenishment operation in a quick and clean manner, toner cartridges are widely used. A typical toner cartridge comprises an elongated vessel filed with an amount of toner. The elongated vessel is adapted to be installed in the machine such that it extends in a horizontal direction. The toner cartridge has an elongated bottom opening for discharging toner, which extends along the length of the toner cartridge. Before installation, the bottom opening is kept closed by a suitable closure member, which may be, for example, a strip of removable sealing tape. After installation of the toner cartridge in the machine, the bottom opening is opened to accomplish toner replenishment. Typically, a toner cartridge of this type is designed to be left in position after installed, until it is replaced with a new one when the replenished amount of toner is again depleted.
Many of the electrophotographic machines using this type of toner cartridge have a toner cartridge slot, defined within a body housing of the machine, for receiving the toner cartridge therein for installation of the toner cartridge in the machine. Typically, the slot (i) is elongated in shape, (ii) extends horizontally and (iii) has a mouth at one longitudinal end, through which the toner cartridge is inserted in and removed from the slot. In such case, the toner cartridge replacement operation involves removal of a used toner cartridge from such slot and insertion of a new one into such slot. This operation, however, is not always easy, in particular when the toner cartridge is relatively large and heavy, due to the relatively tight geometry of the slot. Accordingly, there has been a desire for a suitable means for facilitating toner cartridge replacement operation for an electrophotographic machine having a toner cartridge slot of the above-mentioned type.